Your limbs are maxed when the draw weight checks out at the maximum weight they are rated for. Period.

You CAN get more out of them by twisting the string and cables up to put more preload on the limbs, but that's not really smart. By doing that you put the limbs under excess strain which reduces their service life. You also increase the brace height *** although I must admit I do not know if it works that way for parallel limb bows. Maybe someone who knows can chime in and educate me on that?*** Anyway, raising brace height reduces the bow's power stroke and pretty much erases any speed or energy benefit from overloading the limbs by a couple of pounds.

I like to set up my bows so that I hit peak weight with my limb bolts a full turn from bottomed out. That gives me some cushion to work with in order to fine tune my tiller. Getting the tiller just right is FAR more important than a measely 2-3 extra pounds of draw weight.